Alkyl Nitrate, Hydroxyalkyl Nitrate, and Hydroxycarbonyl Formation from the NOx−Air Photooxidations of C5−C8 n-Alkanes

Abstract

Products of the gas-phase reactions of OH radicals with the n-alkanes n-pentane through n-octane at 298 ± 2 K and atmospheric pressure of air have been investigated using gas chromatography with flame ionization detection (GC-FID), combined gas chromatography−mass spectrometry (GC-MS), and in situ atmospheric pressure ionization tandem mass spectrometry. The formation yields of alkyl nitrates from n-hexane, n-heptane, and n-octane were measured by GC-FID, with the sum of the isomeric alkyl nitrates being 0.141 ± 0.020, 0.178 ± 0.024, and 0.226 ± 0.032, respectively. These alkyl nitrate yields are ∼35% lower than previous data reported from this laboratory in the early 1980s. Using negative ion atmospheric pressure chemical ionization with the addition of pentafluorobenzyl alcohol to study the n-pentane through n-octane reactions and those of the fully deuterated n-alkanes, hydroxyalkyl nitrate products were identified from the n-pentane, n-heptane, and n-octane reactions for the first time and the presenc...